Many implements are known for the performance of domestic yard work, examples being given in the patent literature: U.S. Pat. No. 342,516 issued May 25, 1886; U.S. Pat. No. 375,556 issued Dec. 27, 1887; U.S. Pat. No. 488,918 issued Dec. 27, 1892; U.S. Pat. No. 809,476 issued Jan. 9, 1906; U.S. Pat. No. 840,903 issued Jan. 8, 1907; U.S. Pat. No. 933,227 issued Sep. 7, 1909; U.S. Pat. No. 1,039,012 issued Sep. 17, 1912; U.S. Pat. No. 1,065,456 issued Jun. 24, 1913; U.S. Pat. No. 1,647,832 issued Nov. 1, 1927; Swiss Patent No. 137,681 issued Apr. 1, 1930; U.S. Pat. No. 1,692,436 issued Nov. 20, 1928; U.S. Pat. No. 2,018,279 issued Oct. 22, 1935; U.S. Pat. No. 2,030,770 issued Feb. 11, 1936; Swiss Patent No. 179,360 issued Nov. 16, 1935; U.S. Pat. No. 2,531,297 issued Nov. 21, 1950; U.S. Pat. No. 2,686,690 issued Aug. 17, 1954; British Patent No. 865,902 issued Apr. 19, 1961; U.S. Pat. No. 3,123,391 issued Mar. 3, 1964; U.S. Pat. No. 3,273,930 issued Sep. 20, 1966; U.S. Pat. No. 3,333,881 issued Aug. 1, 1967; U.S. Pat. No. 3,443,830 issued May 13, 1969; U.S. Pat. No. 3,602,542 issued Aug. 31, 1971; U.S. Pat. No. 3,847,227 issued Nov. 12, 1974; U.S. Pat. No. 4,603,744 issued Aug. 5, 1986; U.S. Pat. No. 4,819,735 issued Apr. 11, 1989; U.S. Pat. No. 4,932,339 issued Jun. 12, 1990; U.S. Pat. No. 5,005,888 issued Apr. 9, 1991; Canadian Patent No. 1,290,969 issued Oct. 22, 1991; U.S. Pat. No. 5,242,024 issued Sep. 7, 1993; U.S. Pat. No. 5,338,078 issued Aug. 16, 1994 and U.S. Pat. No. 6,076,614 issued Jun. 20, 2000.
Particularly related to this invention are tools having lower members designed to engage and penetrate the ground through pressing downwardly, and usually an additional rotational force, e.g., prongs or tines at the lower end of shaft, the lower ends of which prongs engage the ground and upon rotation of the shaft dig into the ground to cultivate, aerate, or otherwise till the soil etc. Such tools are described in U.S. Pat. No. 256,039 issued Apr. 4, 1882, U.S. Pat. No. 2,082,476 issued Jan. 17, 1936, U.S. Pat. No. 4,905,768 issued Mar. 6, 1990, U.S. Pat. No. 5,207,466 issued May 4, 1993, U.S. Pat. No. 5,706,900 issued Jan. 13, 1998, U.S. Design Patent No. 406,219 issued Mar. 2, 1999, U.S. Pat. No. 6,467,551 issued Oct. 22, 2002, U.S. Pat. No. 6,536,535 issued Mar. 25, 2003, U.S. Patent Application Publication No. 2003/0230450 published Dec. 18, 2003.